Publishing to a Jekyll blog—or any blog—from Sublime Text 2 involves setting up a Custom Build System, which you can read about in Addy Osmani’s post here.

Create a bash script of the git commands. I called mine publishJekyllPost, and saved it in ~/bin/ (you may need to symlink it to somewhere else—I forget how I got my bin set up). I also had to change permissions for the script, using sudo chmod 755 publishJekyllPost from within the ~/bin/ directory. The chmod value for the file needs to be 755—you can clarify this by running stat -f "%OLp" <file>.

Select the build system for your Markdown documents by choosing it in the menu bar: Tools -> Build System -> Jekyll. Run the Build with CMD + B, and you should see the output of a regular git push command in the Sublime console.